ARM: dts: sun7i: a20: bananapro: Fix ethernet phy-mode

BPi Pro needs TX and RX delay for Gbit to work reliable and avoid high
packet loss rates. The realtek phy driver overrides the settings of the
pull ups for the delays, so fix this for BananaPro.

Fix the phy-mode description to correctly reflect this so that the
implementation doesn't reconfigure the delays incorrectly. This
happened with commit bbc4d71d ("net: phy: realtek: fix rtl8211e
rx/tx delay config").

Fixes: 10662a33

 ("ARM: dts: sun7i: Add dts file for Bananapro board")
Signed-off-by: Hermann Lauer <Hermann.Lauer@uni-heidelberg.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210128111842.GA11919@lemon.iwr.uni-heidelberg.de